Typical freight brake control valves include a pipe bracket portion having a service portion and an emergency portion mounted on opposite sides or faces of the pipe bracket. Such typical prior art brake control valve assembly is shown diagrammatically in FIG. 1. Typically, the rear side of the pipe bracket portion has a number of locations for connecting the pipe bracket portion to the piping of the freight car. These rear locations generally will include the connections to the brake pipe, the brake cylinder retaining valve, the brake cylinder, the emergency reservoir and the auxiliary reservoir.
These pipe bracket connections to the pneumatic piping permits the pipe bracket to provide the necessary communication of fluid pressures to both the service and emergency portions of the brake control valve as well as to the brake cylinder and reservoirs.
Most type AB pipe brackets only have connections to pipe lines on the rear surface. However, since it is sometimes necessary to tap into the fluid lines for the purpose of obtaining pressure measurements of the fluid within the piping, such access to the fluid is frequently quite difficult depending on the placement of the brake control valve on the freight car. In addition, the connections between the pipe bracket and the freight car piping would require them to be broken to allow monitoring of the pressures.
Recent modifications to the AB brake pipe bracket have provided direct access to the fluid passageways through the front side of the pipe bracket on the freight brake control valve. This modification eliminates the need to access the rear side of the freight brake control valve. The front side test ports provide access to the brake pipe line, the brake cylinder, the emergency reservoir and the auxiliary reservoir. Providing these test ports on the front side of the pipe bracket enables the testing of the fluid pressures within the pipe bracket without having to remove the freight brake control valve from the car or the service portion or the emergency portion from the pipe bracket portion.
Such brake pipe bracket modification has been disclosed in U.S. patent application Ser. No. 08/547,929, which is assigned to the Westinghouse Air Brake Company. The automated single car brake tester has been disclosed in U.S. patent application Ser. No. 08/396,815 and is, also, assigned to Westinghouse Air Brake Company.
The test ports on the front side of the pipe bracket provide a significant improvement over the old pipe bracket by providing access to the passageways in the pipe bracket without having to disconnect the normal fluid lines connected to the rear side of the pipe bracket portion. However, this modification only provides for a side access to the pipe bracket portion. Unfortunately, there may be instances where car builders cannot utilize the side access, which has vertically disposed test ports, and may prefer or require a top or a bottom access.